Just purchased the boat a month ago now and starting on stereo work and wanted to figure out why the Kicker 12" sub under the driver area wasn't hitting very hard. So we pulled it out (literally) and this is what we found:

The box came apart in my hand and the woofer terminals were corroded horribly. So incase anyone was wondering thats speaker install was done by a 'pro audio' shop in Dallas Texas about a year ago. Ha

People are so stupid. Stupid for many different reason's. That box could be junk for the same reasons I think people are so stupid. Ill give some examples.

The way I use my boat I could get away with not putting resin or waterproofing sub boxes. My boat doesn’t sit out in the rain ever. I don't submarine the boat yea water might splash in the front on accident but its not enough to worry about. If your one of the people that says "Its a boat it's supposed to get wet" Your a idiot! In normal use water doesn’t get near electronics’. Many Many people have 100% car audio or Non Marine gear in their boat with no problems. I have NEVER had a problem with any electronic device going bad under "normal" use. The one and only thing that I had a problem was an EQ taking a direct hit from a friends little girl spraying the EQ with a super soaker this was abuse on my part and yes it went bad. But like I said under normal use you should have no problems. Now your definition of "Normal" use might be way different than myn, Some examples, people might think normal use is. leaving the boat out in the rain, or with a cover that's either not existent or one that let's water in and fresh air out. Driving the boat to "Dip" the bow under water to cool people off. Forgetting to take the drain plug out and letting the boat fill with water, letting your boat sit wet under the cover and then when the sun hits it MOLD city. Boats with 2 feet of snow on top of them. Boats sitting outside in direct sunlight all year and summer with no cover getting sun baked. I could go on an on but if you fit in any of these categories, your a straight up idiot and you deserve or should drive a bayliner with hard plastic seat's. It's your boat you can do or run it how ever you feel. I just think it totally ghetto to get something you can't or don't take care of. Yea you can afford the boat payment but you cant afford to store it some where that keeps it nice= Straight GHETTO. Some boats are used to complete a job they are not in this category. But if you have a wake boat IMO that's a luxury item its not like you have to have it. IMO if you can't take care of it (At least keep it covered and clean) then you don't deserve it. This is just my opinion and I know Im weird. Some people just don't care. I get it. They let the boat get thrashed and then just deal with it. To each their own.

Finally a pic that really shows why MDF is SO inappropriate for this application.

I personally fall in the same category as Grant. My stuff never sits out in the rain, except at the dock on that weekend when we get a brief rain shower. I store indoors and never put a cover on until winter layup to keep mold out of the boat and everything dry.

Still, I would never knowingly install MDF in my boat.

I will recommend that you try to use a void-free plywood, (13-ply or more for 3/4") for subwoofer enclosure construction. MDF is just too hygroscopic and it swells so much in high humidity. Lots of folks have had success with sealing MDF with resin or epoxy or whatever, but having been around old wood boats, I know how much wood can shrink and swell just due to humidity changes. I know how tough that movement is on adhesives, finish, fasteners, etc.. Once you get a crack or a void in your sealant coating, water will get in, and once it is in, the cover coating makes it hard for the moisture to escape.

Try and find 13-ply marine or cabinet-grade plywood for your subwoofer enclosures. They will last a LOT longer...

Scotty-

What amplifier do you have right now on the sub? TigeMike is right, you have an opportunity to move up the food chain and get a bigger amp and a badder woofer, but you might have the juice already.

Even if the box was resined, if it was sitting on the floor in a place that was exposed to water occasionally, the resin will not protect 100%. The box needs to be raised off the floor, use some sort of plastic feet. If nto, water will eventualy be wicked up into the box.

I thought I have seen several boats with boxes placed in that location, do all these guys use something special to keep water from absorbing into the boxes?

Adam - I will be putting the next box on some kind of stilts to keep it off the floor and may even go with the woofer firing downward for more reverb than shooting directly out at the driver.

Phil - The amp I have(had) running that kicker sub is a Kicker 350X.2 (I think thats what its called). I have never been a big fan of kicker and this obviously didn't help my case. I have a local Memphis audio dealer interested in building a box with some of thier marine grade sub's and fiberglassing a custom box. IF I was to go with a Kicker sub, what would you recommend? This will probably be the only sub in the boat and I would like a solid sound. I have the kicker KMT6's for tower just so you know what I need matched up sound-wise...

An installer that is not familiar with the demands of the marine environment can make that mistake with any brand. I can tell by the pics that what you have is not a factory Kicker box.

Adam makes a point I neglected. The enclosure should be elevated to prevent moisture wicking.

If you are going to rely on a single sub, in that location, a good recommendation will be to use a Comp VR 12 like TigeMike shared. The very specific woofer you want to use with the ZX or KX350.2 will be the CVR122. It has dual 2-ohm voice coils, which will allow you to put one voice coil on each amp channel and max the amp out.

Fiberglass is a good enclosure choice, or the void-free plywood as I recommend above.

A point I want to make in closing. The woofer you just removed has a stamped - steel frame. the Comp VR also has a stamped steel frame. If you are going to be getting the woofer into more wetness, I want to recommend that regardless of brand, you go for a composite or aluminum-basket woofer. Steel will rust no matter what you do to it. That is why I made totally sure that the marine Kicker KM10 marine subwoofers were built on a totally rust-proof injection-molded basket. If you want to use a round 12, in a sililarly-sized enclosure, try the Kicker CVX122 on that amp. The woofer will handle more power, but you will not have the rust issues you have with a stamped steel basket living in a wet environment.

I want to also add that if you wanted to go with a couple of 10's the Kicker Marine Audio KM10 woofers would be nice on that amp. They are water-proof, they are extremely musical, and with two, you could put one in the same location, and the other under the rear deck or some similar place where it an be appreciated.

The 350.2 delivers 110 watts into each 4-ohm load, a tiny bit low for the KM10's but you would have more surface area compared to a single 12.

You would also not have the rust issues that you will find with automotive products if you are going to be getting them wet on a regular basis...

We see that sceneria about once a week where the box appears to be good from the outside but is only held together by the vinyl or carpet.

The first rule is to elevate the box off the carpeted sole regardless of what material you use to construct the box. You must eliminate the moisture trap.

MDF is rigid and acoustically inert so its ideal from a sonic standpoint. It will last if you coat it correctly. There's a long list of dos and donts. But for added insurance there is an exterior grade of MDF called MEDEX that is constructed with solvent-based adhesives versus water-based. But I would coat it anyway.